net/tipc/link.c

   1 /*
   2  * net/tipc/link.c: TIPC link code
   3  *
   4  * Copyright (c) 1996-2007, 2012-2015, Ericsson AB
   5  * Copyright (c) 2004-2007, 2010-2013, Wind River Systems
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the names of the copyright holders nor the names of its
  17  *    contributors may be used to endorse or promote products derived from
  18  *    this software without specific prior written permission.
  19  *
  20  * Alternatively, this software may be distributed under the terms of the
  21  * GNU General Public License ("GPL") version 2 as published by the Free
  22  * Software Foundation.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  25  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  28  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  29  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  30  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  32  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  33  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  34  * POSSIBILITY OF SUCH DAMAGE.
  35  */
  36
  37 #include "core.h"
  38 #include "subscr.h"
  39 #include "link.h"
  40 #include "bcast.h"
  41 #include "socket.h"
  42 #include "name_distr.h"
  43 #include "discover.h"
  44 #include "netlink.h"
  45
  46 #include <linux/pkt_sched.h>
  47
  48 /*
  49  * Error message prefixes
  50  */
  51 static const char *link_co_err = "Link tunneling error, ";
  52 static const char *link_rst_msg = "Resetting link ";
  53 static const char *link_unk_evt = "Unknown link event ";
  54
  55 static const struct nla_policy tipc_nl_link_policy[TIPC_NLA_LINK_MAX + 1] = {
  56         [TIPC_NLA_LINK_UNSPEC]          = { .type = NLA_UNSPEC },
  57         [TIPC_NLA_LINK_NAME] = {
  58                 .type = NLA_STRING,
  59                 .len = TIPC_MAX_LINK_NAME
  60         },
  61         [TIPC_NLA_LINK_MTU]             = { .type = NLA_U32 },
  62         [TIPC_NLA_LINK_BROADCAST]       = { .type = NLA_FLAG },
  63         [TIPC_NLA_LINK_UP]              = { .type = NLA_FLAG },
  64         [TIPC_NLA_LINK_ACTIVE]          = { .type = NLA_FLAG },
  65         [TIPC_NLA_LINK_PROP]            = { .type = NLA_NESTED },
  66         [TIPC_NLA_LINK_STATS]           = { .type = NLA_NESTED },
  67         [TIPC_NLA_LINK_RX]              = { .type = NLA_U32 },
  68         [TIPC_NLA_LINK_TX]              = { .type = NLA_U32 }
  69 };
  70
  71 /* Properties valid for media, bearar and link */
  72 static const struct nla_policy tipc_nl_prop_policy[TIPC_NLA_PROP_MAX + 1] = {
  73         [TIPC_NLA_PROP_UNSPEC]          = { .type = NLA_UNSPEC },
  74         [TIPC_NLA_PROP_PRIO]            = { .type = NLA_U32 },
  75         [TIPC_NLA_PROP_TOL]             = { .type = NLA_U32 },
  76         [TIPC_NLA_PROP_WIN]             = { .type = NLA_U32 }
  77 };
  78
  79 /*
  80  * Interval between NACKs when packets arrive out of order
  81  */
  82 #define TIPC_NACK_INTV (TIPC_MIN_LINK_WIN * 2)
  83 /*
  84  * Out-of-range value for link session numbers
  85  */
  86 #define WILDCARD_SESSION 0x10000
  87
  88 /* State value stored in 'failover_pkts'
  89  */
  90 #define FIRST_FAILOVER 0xffffu
  91
  92 /* Link FSM states and events:
  93  */
  94 enum {
  95         TIPC_LINK_WORKING,
  96         TIPC_LINK_PROBING,
  97         TIPC_LINK_RESETTING,
  98         TIPC_LINK_ESTABLISHING
  99 };
 100
 101 enum {
 102         PEER_RESET_EVT    = RESET_MSG,
 103         ACTIVATE_EVT      = ACTIVATE_MSG,
 104         TRAFFIC_EVT,      /* Any other valid msg from peer */
 105         SILENCE_EVT       /* Peer was silent during last timer interval*/
 106 };
 107
 108 /* Link FSM state checking routines
 109  */
 110 static int link_working(struct tipc_link *l)
 111 {
 112         return l->state == TIPC_LINK_WORKING;
 113 }
 114
 115 static int link_probing(struct tipc_link *l)
 116 {
 117         return l->state == TIPC_LINK_PROBING;
 118 }
 119
 120 static int link_resetting(struct tipc_link *l)
 121 {
 122         return l->state == TIPC_LINK_RESETTING;
 123 }
 124
 125 static int link_establishing(struct tipc_link *l)
 126 {
 127         return l->state == TIPC_LINK_ESTABLISHING;
 128 }
 129
 130 static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
 131                                struct sk_buff_head *xmitq);
 132 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
 133                                       u16 rcvgap, int tolerance, int priority,
 134                                       struct sk_buff_head *xmitq);
 135 static void link_reset_statistics(struct tipc_link *l_ptr);
 136 static void link_print(struct tipc_link *l_ptr, const char *str);
 137 static void tipc_link_sync_rcv(struct tipc_node *n, struct sk_buff *buf);
 138 static int tipc_link_input(struct tipc_link *l, struct sk_buff *skb);
 139 static bool tipc_data_input(struct tipc_link *l, struct sk_buff *skb);
 140
 141 /*
 142  *  Simple non-static link routines (i.e. referenced outside this file)
 143  */
 144 int tipc_link_is_up(struct tipc_link *l_ptr)
 145 {
 146         if (!l_ptr)
 147                 return 0;
 148         return link_working(l_ptr) || link_probing(l_ptr);
 149 }
 150
 151 int tipc_link_is_active(struct tipc_link *l)
 152 {
 153         struct tipc_node *n = l->owner;
 154
 155         return (node_active_link(n, 0) == l) || (node_active_link(n, 1) == l);
 156 }
 157
 158 /**
 159  * tipc_link_create - create a new link
 160  * @n_ptr: pointer to associated node
 161  * @b_ptr: pointer to associated bearer
 162  * @media_addr: media address to use when sending messages over link
 163  *
 164  * Returns pointer to link.
 165  */
 166 struct tipc_link *tipc_link_create(struct tipc_node *n_ptr,
 167                                    struct tipc_bearer *b_ptr,
 168                                    const struct tipc_media_addr *media_addr,
 169                                    struct sk_buff_head *inputq,
 170                                    struct sk_buff_head *namedq)
 171 {
 172         struct tipc_net *tn = net_generic(n_ptr->net, tipc_net_id);
 173         struct tipc_link *l_ptr;
 174         struct tipc_msg *msg;
 175         char *if_name;
 176         char addr_string[16];
 177         u32 peer = n_ptr->addr;
 178
 179         if (n_ptr->link_cnt >= MAX_BEARERS) {
 180                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 181                 pr_err("Cannot establish %uth link to %s. Max %u allowed.\n",
 182                        n_ptr->link_cnt, addr_string, MAX_BEARERS);
 183                 return NULL;
 184         }
 185
 186         if (n_ptr->links[b_ptr->identity].link) {
 187                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 188                 pr_err("Attempt to establish second link on <%s> to %s\n",
 189                        b_ptr->name, addr_string);
 190                 return NULL;
 191         }
 192
 193         l_ptr = kzalloc(sizeof(*l_ptr), GFP_ATOMIC);
 194         if (!l_ptr) {
 195                 pr_warn("Link creation failed, no memory\n");
 196                 return NULL;
 197         }
 198         l_ptr->addr = peer;
 199         if_name = strchr(b_ptr->name, ':') + 1;
 200         sprintf(l_ptr->name, "%u.%u.%u:%s-%u.%u.%u:unknown",
 201                 tipc_zone(tn->own_addr), tipc_cluster(tn->own_addr),
 202                 tipc_node(tn->own_addr),
 203                 if_name,
 204                 tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
 205                 /* note: peer i/f name is updated by reset/activate message */
 206         memcpy(&l_ptr->media_addr, media_addr, sizeof(*media_addr));
 207         l_ptr->owner = n_ptr;
 208         l_ptr->peer_session = WILDCARD_SESSION;
 209         l_ptr->bearer_id = b_ptr->identity;
 210         l_ptr->tolerance = b_ptr->tolerance;
 211         l_ptr->snd_nxt = 1;
 212         l_ptr->rcv_nxt = 1;
 213         l_ptr->state = TIPC_LINK_RESETTING;
 214
 215         l_ptr->pmsg = (struct tipc_msg *)&l_ptr->proto_msg;
 216         msg = l_ptr->pmsg;
 217         tipc_msg_init(tn->own_addr, msg, LINK_PROTOCOL, RESET_MSG, INT_H_SIZE,
 218                       l_ptr->addr);
 219         msg_set_size(msg, sizeof(l_ptr->proto_msg));
 220         msg_set_session(msg, (tn->random & 0xffff));
 221         msg_set_bearer_id(msg, b_ptr->identity);
 222         strcpy((char *)msg_data(msg), if_name);
 223         l_ptr->net_plane = b_ptr->net_plane;
 224         l_ptr->advertised_mtu = b_ptr->mtu;
 225         l_ptr->mtu = l_ptr->advertised_mtu;
 226         l_ptr->priority = b_ptr->priority;
 227         tipc_link_set_queue_limits(l_ptr, b_ptr->window);
 228         l_ptr->snd_nxt = 1;
 229         __skb_queue_head_init(&l_ptr->transmq);
 230         __skb_queue_head_init(&l_ptr->backlogq);
 231         __skb_queue_head_init(&l_ptr->deferdq);
 232         skb_queue_head_init(&l_ptr->wakeupq);
 233         l_ptr->inputq = inputq;
 234         l_ptr->namedq = namedq;
 235         skb_queue_head_init(l_ptr->inputq);
 236         link_reset_statistics(l_ptr);
 237         tipc_node_attach_link(n_ptr, l_ptr);
 238         return l_ptr;
 239 }
 240
 241 /* tipc_link_build_bcast_sync_msg() - synchronize broadcast link endpoints.
 242  *
 243  * Give a newly added peer node the sequence number where it should
 244  * start receiving and acking broadcast packets.
 245  */
 246 void tipc_link_build_bcast_sync_msg(struct tipc_link *l,
 247                                     struct sk_buff_head *xmitq)
 248 {
 249         struct sk_buff *skb;
 250         struct sk_buff_head list;
 251         u16 last_sent;
 252
 253         skb = tipc_msg_create(BCAST_PROTOCOL, STATE_MSG, INT_H_SIZE,
 254                               0, l->addr, link_own_addr(l), 0, 0, 0);
 255         if (!skb)
 256                 return;
 257         last_sent = tipc_bclink_get_last_sent(l->owner->net);
 258         msg_set_last_bcast(buf_msg(skb), last_sent);
 259         __skb_queue_head_init(&list);
 260         __skb_queue_tail(&list, skb);
 261         tipc_link_xmit(l, &list, xmitq);
 262 }
 263
 264 /**
 265  * tipc_link_fsm_evt - link finite state machine
 266  * @l: pointer to link
 267  * @evt: state machine event to be processed
 268  * @xmitq: queue to prepend created protocol message, if any
 269  */
 270 static int tipc_link_fsm_evt(struct tipc_link *l, int evt,
 271                              struct sk_buff_head *xmitq)
 272 {
 273         int rc = 0;
 274         struct tipc_link *pl;
 275         enum {
 276                 LINK_RESET     = 1,
 277                 LINK_ACTIVATE  = (1 << 1),
 278                 SND_PROBE      = (1 << 2),
 279                 SND_STATE      = (1 << 3),
 280                 SND_RESET      = (1 << 4),
 281                 SND_ACTIVATE   = (1 << 5),
 282                 SND_BCAST_SYNC = (1 << 6)
 283         } actions = 0;
 284
 285         if (l->exec_mode == TIPC_LINK_BLOCKED)
 286                 return rc;
 287
 288         switch (l->state) {
 289         case TIPC_LINK_WORKING:
 290                 switch (evt) {
 291                 case TRAFFIC_EVT:
 292                 case ACTIVATE_EVT:
 293                         break;
 294                 case SILENCE_EVT:
 295                         l->state = TIPC_LINK_PROBING;
 296                         actions |= SND_PROBE;
 297                         break;
 298                 case PEER_RESET_EVT:
 299                         actions |= LINK_RESET | SND_ACTIVATE;
 300                         break;
 301                 default:
 302                         pr_debug("%s%u WORKING\n", link_unk_evt, evt);
 303                 }
 304                 break;
 305         case TIPC_LINK_PROBING:
 306                 switch (evt) {
 307                 case TRAFFIC_EVT:
 308                 case ACTIVATE_EVT:
 309                         l->state = TIPC_LINK_WORKING;
 310                         break;
 311                 case PEER_RESET_EVT:
 312                         actions |= LINK_RESET | SND_ACTIVATE;
 313                         break;
 314                 case SILENCE_EVT:
 315                         if (l->silent_intv_cnt <= l->abort_limit) {
 316                                 actions |= SND_PROBE;
 317                                 break;
 318                         }
 319                         actions |= LINK_RESET | SND_RESET;
 320                         break;
 321                 default:
 322                         pr_err("%s%u PROBING\n", link_unk_evt, evt);
 323                 }
 324                 break;
 325         case TIPC_LINK_RESETTING:
 326                 switch (evt) {
 327                 case TRAFFIC_EVT:
 328                         break;
 329                 case ACTIVATE_EVT:
 330                         pl = node_active_link(l->owner, 0);
 331                         if (pl && link_probing(pl))
 332                                 break;
 333                         l->state = TIPC_LINK_WORKING;
 334                         actions |= LINK_ACTIVATE;
 335                         if (!l->owner->working_links)
 336                                 actions |= SND_BCAST_SYNC;
 337                         break;
 338                 case PEER_RESET_EVT:
 339                         l->state = TIPC_LINK_ESTABLISHING;
 340                         actions |= SND_ACTIVATE;
 341                         break;
 342                 case SILENCE_EVT:
 343                         actions |= SND_RESET;
 344                         break;
 345                 default:
 346                         pr_err("%s%u in RESETTING\n", link_unk_evt, evt);
 347                 }
 348                 break;
 349         case TIPC_LINK_ESTABLISHING:
 350                 switch (evt) {
 351                 case TRAFFIC_EVT:
 352                 case ACTIVATE_EVT:
 353                         pl = node_active_link(l->owner, 0);
 354                         if (pl && link_probing(pl))
 355                                 break;
 356                         l->state = TIPC_LINK_WORKING;
 357                         actions |= LINK_ACTIVATE;
 358                         if (!l->owner->working_links)
 359                                 actions |= SND_BCAST_SYNC;
 360                         break;
 361                 case PEER_RESET_EVT:
 362                         break;
 363                 case SILENCE_EVT:
 364                         actions |= SND_ACTIVATE;
 365                         break;
 366                 default:
 367                         pr_err("%s%u ESTABLISHING\n", link_unk_evt, evt);
 368                 }
 369                 break;
 370         default:
 371                 pr_err("Unknown link state %u/%u\n", l->state, evt);
 372         }
 373
 374         /* Perform actions as decided by FSM */
 375         if (actions & LINK_RESET) {
 376                 l->exec_mode = TIPC_LINK_BLOCKED;
 377                 rc = TIPC_LINK_DOWN_EVT;
 378         }
 379         if (actions & LINK_ACTIVATE)
 380                 rc = TIPC_LINK_UP_EVT;
 381
 382         return rc;
 383 }
 384
 385 /* link_profile_stats - update statistical profiling of traffic
 386  */
 387 static void link_profile_stats(struct tipc_link *l)
 388 {
 389         struct sk_buff *skb;
 390         struct tipc_msg *msg;
 391         int length;
 392
 393         /* Update counters used in statistical profiling of send traffic */
 394         l->stats.accu_queue_sz += skb_queue_len(&l->transmq);
 395         l->stats.queue_sz_counts++;
 396
 397         skb = skb_peek(&l->transmq);
 398         if (!skb)
 399                 return;
 400         msg = buf_msg(skb);
 401         length = msg_size(msg);
 402
 403         if (msg_user(msg) == MSG_FRAGMENTER) {
 404                 if (msg_type(msg) != FIRST_FRAGMENT)
 405                         return;
 406                 length = msg_size(msg_get_wrapped(msg));
 407         }
 408         l->stats.msg_lengths_total += length;
 409         l->stats.msg_length_counts++;
 410         if (length <= 64)
 411                 l->stats.msg_length_profile[0]++;
 412         else if (length <= 256)
 413                 l->stats.msg_length_profile[1]++;
 414         else if (length <= 1024)
 415                 l->stats.msg_length_profile[2]++;
 416         else if (length <= 4096)
 417                 l->stats.msg_length_profile[3]++;
 418         else if (length <= 16384)
 419                 l->stats.msg_length_profile[4]++;
 420         else if (length <= 32768)
 421                 l->stats.msg_length_profile[5]++;
 422         else
 423                 l->stats.msg_length_profile[6]++;
 424 }
 425
 426 /* tipc_link_timeout - perform periodic task as instructed from node timeout
 427  */
 428 int tipc_link_timeout(struct tipc_link *l, struct sk_buff_head *xmitq)
 429 {
 430         int rc = 0;
 431         int mtyp = STATE_MSG;
 432         bool xmit = false;
 433         bool prb = false;
 434
 435         if (l->exec_mode == TIPC_LINK_BLOCKED)
 436                 return rc;
 437
 438         link_profile_stats(l);
 439
 440         if (l->state == TIPC_LINK_WORKING) {
 441                 if (!l->silent_intv_cnt) {
 442                         if (tipc_bclink_acks_missing(l->owner))
 443                                 xmit = true;
 444                 } else if (l->silent_intv_cnt <= l->abort_limit) {
 445                         xmit = true;
 446                         prb = true;
 447                 } else {
 448                         l->exec_mode = TIPC_LINK_BLOCKED;
 449                         rc |= TIPC_LINK_DOWN_EVT;
 450                 }
 451                 l->silent_intv_cnt++;
 452         } else if (l->state == TIPC_LINK_RESETTING) {
 453                 xmit = true;
 454                 mtyp = RESET_MSG;
 455         } else if (l->state == TIPC_LINK_ESTABLISHING) {
 456                 xmit = true;
 457                 mtyp = ACTIVATE_MSG;
 458         }
 459         if (xmit)
 460                 tipc_link_build_proto_msg(l, mtyp, prb, 0, 0, 0, xmitq);
 461
 462         return rc;
 463 }
 464
 465 /**
 466  * link_schedule_user - schedule a message sender for wakeup after congestion
 467  * @link: congested link
 468  * @list: message that was attempted sent
 469  * Create pseudo msg to send back to user when congestion abates
 470  * Does not consume buffer list
 471  */
 472 static int link_schedule_user(struct tipc_link *link, struct sk_buff_head *list)
 473 {
 474         struct tipc_msg *msg = buf_msg(skb_peek(list));
 475         int imp = msg_importance(msg);
 476         u32 oport = msg_origport(msg);
 477         u32 addr = link_own_addr(link);
 478         struct sk_buff *skb;
 479
 480         /* This really cannot happen...  */
 481         if (unlikely(imp > TIPC_CRITICAL_IMPORTANCE)) {
 482                 pr_warn("%s<%s>, send queue full", link_rst_msg, link->name);
 483                 return -ENOBUFS;
 484         }
 485         /* Non-blocking sender: */
 486         if (TIPC_SKB_CB(skb_peek(list))->wakeup_pending)
 487                 return -ELINKCONG;
 488
 489         /* Create and schedule wakeup pseudo message */
 490         skb = tipc_msg_create(SOCK_WAKEUP, 0, INT_H_SIZE, 0,
 491                               addr, addr, oport, 0, 0);
 492         if (!skb)
 493                 return -ENOBUFS;
 494         TIPC_SKB_CB(skb)->chain_sz = skb_queue_len(list);
 495         TIPC_SKB_CB(skb)->chain_imp = imp;
 496         skb_queue_tail(&link->wakeupq, skb);
 497         link->stats.link_congs++;
 498         return -ELINKCONG;
 499 }
 500
 501 /**
 502  * link_prepare_wakeup - prepare users for wakeup after congestion
 503  * @link: congested link
 504  * Move a number of waiting users, as permitted by available space in
 505  * the send queue, from link wait queue to node wait queue for wakeup
 506  */
 507 void link_prepare_wakeup(struct tipc_link *l)
 508 {
 509         int pnd[TIPC_SYSTEM_IMPORTANCE + 1] = {0,};
 510         int imp, lim;
 511         struct sk_buff *skb, *tmp;
 512
 513         skb_queue_walk_safe(&l->wakeupq, skb, tmp) {
 514                 imp = TIPC_SKB_CB(skb)->chain_imp;
 515                 lim = l->window + l->backlog[imp].limit;
 516                 pnd[imp] += TIPC_SKB_CB(skb)->chain_sz;
 517                 if ((pnd[imp] + l->backlog[imp].len) >= lim)
 518                         break;
 519                 skb_unlink(skb, &l->wakeupq);
 520                 skb_queue_tail(l->inputq, skb);
 521                 l->owner->inputq = l->inputq;
 522                 l->owner->action_flags |= TIPC_MSG_EVT;
 523         }
 524 }
 525
 526 /**
 527  * tipc_link_reset_fragments - purge link's inbound message fragments queue
 528  * @l_ptr: pointer to link
 529  */
 530 void tipc_link_reset_fragments(struct tipc_link *l_ptr)
 531 {
 532         kfree_skb(l_ptr->reasm_buf);
 533         l_ptr->reasm_buf = NULL;
 534 }
 535
 536 void tipc_link_purge_backlog(struct tipc_link *l)
 537 {
 538         __skb_queue_purge(&l->backlogq);
 539         l->backlog[TIPC_LOW_IMPORTANCE].len = 0;
 540         l->backlog[TIPC_MEDIUM_IMPORTANCE].len = 0;
 541         l->backlog[TIPC_HIGH_IMPORTANCE].len = 0;
 542         l->backlog[TIPC_CRITICAL_IMPORTANCE].len = 0;
 543         l->backlog[TIPC_SYSTEM_IMPORTANCE].len = 0;
 544 }
 545
 546 /**
 547  * tipc_link_purge_queues - purge all pkt queues associated with link
 548  * @l_ptr: pointer to link
 549  */
 550 void tipc_link_purge_queues(struct tipc_link *l_ptr)
 551 {
 552         __skb_queue_purge(&l_ptr->deferdq);
 553         __skb_queue_purge(&l_ptr->transmq);
 554         tipc_link_purge_backlog(l_ptr);
 555         tipc_link_reset_fragments(l_ptr);
 556 }
 557
 558 void tipc_link_reset(struct tipc_link *l)
 559 {
 560         struct tipc_node *owner = l->owner;
 561
 562         l->state = TIPC_LINK_RESETTING;
 563
 564         /* Link is down, accept any session */
 565         l->peer_session = WILDCARD_SESSION;
 566
 567         /* If peer is up, it only accepts an incremented session number */
 568         msg_set_session(l->pmsg, msg_session(l->pmsg) + 1);
 569
 570         /* Prepare for renewed mtu size negotiation */
 571         l->mtu = l->advertised_mtu;
 572
 573         /* Clean up all queues, except inputq: */
 574         __skb_queue_purge(&l->transmq);
 575         __skb_queue_purge(&l->deferdq);
 576         if (!owner->inputq)
 577                 owner->inputq = l->inputq;
 578         skb_queue_splice_init(&l->wakeupq, owner->inputq);
 579         if (!skb_queue_empty(owner->inputq))
 580                 owner->action_flags |= TIPC_MSG_EVT;
 581
 582         tipc_link_purge_backlog(l);
 583         kfree_skb(l->reasm_buf);
 584         kfree_skb(l->failover_reasm_skb);
 585         l->reasm_buf = NULL;
 586         l->failover_reasm_skb = NULL;
 587         l->rcv_unacked = 0;
 588         l->snd_nxt = 1;
 589         l->rcv_nxt = 1;
 590         l->silent_intv_cnt = 0;
 591         l->stats.recv_info = 0;
 592         l->stale_count = 0;
 593         link_reset_statistics(l);
 594 }
 595
 596 /**
 597  * __tipc_link_xmit(): same as tipc_link_xmit, but destlink is known & locked
 598  * @link: link to use
 599  * @list: chain of buffers containing message
 600  *
 601  * Consumes the buffer chain, except when returning an error code,
 602  * Returns 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
 603  * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
 604  */
 605 int __tipc_link_xmit(struct net *net, struct tipc_link *link,
 606                      struct sk_buff_head *list)
 607 {
 608         struct tipc_msg *msg = buf_msg(skb_peek(list));
 609         unsigned int maxwin = link->window;
 610         unsigned int i, imp = msg_importance(msg);
 611         uint mtu = link->mtu;
 612         u16 ack = mod(link->rcv_nxt - 1);
 613         u16 seqno = link->snd_nxt;
 614         u16 bc_last_in = link->owner->bclink.last_in;
 615         struct tipc_media_addr *addr = &link->media_addr;
 616         struct sk_buff_head *transmq = &link->transmq;
 617         struct sk_buff_head *backlogq = &link->backlogq;
 618         struct sk_buff *skb, *bskb;
 619
 620         /* Match msg importance against this and all higher backlog limits: */
 621         for (i = imp; i <= TIPC_SYSTEM_IMPORTANCE; i++) {
 622                 if (unlikely(link->backlog[i].len >= link->backlog[i].limit))
 623                         return link_schedule_user(link, list);
 624         }
 625         if (unlikely(msg_size(msg) > mtu))
 626                 return -EMSGSIZE;
 627
 628         /* Prepare each packet for sending, and add to relevant queue: */
 629         while (skb_queue_len(list)) {
 630                 skb = skb_peek(list);
 631                 msg = buf_msg(skb);
 632                 msg_set_seqno(msg, seqno);
 633                 msg_set_ack(msg, ack);
 634                 msg_set_bcast_ack(msg, bc_last_in);
 635
 636                 if (likely(skb_queue_len(transmq) < maxwin)) {
 637                         __skb_dequeue(list);
 638                         __skb_queue_tail(transmq, skb);
 639                         tipc_bearer_send(net, link->bearer_id, skb, addr);
 640                         link->rcv_unacked = 0;
 641                         seqno++;
 642                         continue;
 643                 }
 644                 if (tipc_msg_bundle(skb_peek_tail(backlogq), msg, mtu)) {
 645                         kfree_skb(__skb_dequeue(list));
 646                         link->stats.sent_bundled++;
 647                         continue;
 648                 }
 649                 if (tipc_msg_make_bundle(&bskb, msg, mtu, link->addr)) {
 650                         kfree_skb(__skb_dequeue(list));
 651                         __skb_queue_tail(backlogq, bskb);
 652                         link->backlog[msg_importance(buf_msg(bskb))].len++;
 653                         link->stats.sent_bundled++;
 654                         link->stats.sent_bundles++;
 655                         continue;
 656                 }
 657                 link->backlog[imp].len += skb_queue_len(list);
 658                 skb_queue_splice_tail_init(list, backlogq);
 659         }
 660         link->snd_nxt = seqno;
 661         return 0;
 662 }
 663
 664 /**
 665  * tipc_link_xmit(): enqueue buffer list according to queue situation
 666  * @link: link to use
 667  * @list: chain of buffers containing message
 668  * @xmitq: returned list of packets to be sent by caller
 669  *
 670  * Consumes the buffer chain, except when returning -ELINKCONG,
 671  * since the caller then may want to make more send attempts.
 672  * Returns 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
 673  * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
 674  */
 675 int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
 676                    struct sk_buff_head *xmitq)
 677 {
 678         struct tipc_msg *hdr = buf_msg(skb_peek(list));
 679         unsigned int maxwin = l->window;
 680         unsigned int i, imp = msg_importance(hdr);
 681         unsigned int mtu = l->mtu;
 682         u16 ack = l->rcv_nxt - 1;
 683         u16 seqno = l->snd_nxt;
 684         u16 bc_last_in = l->owner->bclink.last_in;
 685         struct sk_buff_head *transmq = &l->transmq;
 686         struct sk_buff_head *backlogq = &l->backlogq;
 687         struct sk_buff *skb, *_skb, *bskb;
 688
 689         /* Match msg importance against this and all higher backlog limits: */
 690         for (i = imp; i <= TIPC_SYSTEM_IMPORTANCE; i++) {
 691                 if (unlikely(l->backlog[i].len >= l->backlog[i].limit))
 692                         return link_schedule_user(l, list);
 693         }
 694         if (unlikely(msg_size(hdr) > mtu))
 695                 return -EMSGSIZE;
 696
 697         /* Prepare each packet for sending, and add to relevant queue: */
 698         while (skb_queue_len(list)) {
 699                 skb = skb_peek(list);
 700                 hdr = buf_msg(skb);
 701                 msg_set_seqno(hdr, seqno);
 702                 msg_set_ack(hdr, ack);
 703                 msg_set_bcast_ack(hdr, bc_last_in);
 704
 705                 if (likely(skb_queue_len(transmq) < maxwin)) {
 706                         _skb = skb_clone(skb, GFP_ATOMIC);
 707                         if (!_skb)
 708                                 return -ENOBUFS;
 709                         __skb_dequeue(list);
 710                         __skb_queue_tail(transmq, skb);
 711                         __skb_queue_tail(xmitq, _skb);
 712                         l->rcv_unacked = 0;
 713                         seqno++;
 714                         continue;
 715                 }
 716                 if (tipc_msg_bundle(skb_peek_tail(backlogq), hdr, mtu)) {
 717                         kfree_skb(__skb_dequeue(list));
 718                         l->stats.sent_bundled++;
 719                         continue;
 720                 }
 721                 if (tipc_msg_make_bundle(&bskb, hdr, mtu, l->addr)) {
 722                         kfree_skb(__skb_dequeue(list));
 723                         __skb_queue_tail(backlogq, bskb);
 724                         l->backlog[msg_importance(buf_msg(bskb))].len++;
 725                         l->stats.sent_bundled++;
 726                         l->stats.sent_bundles++;
 727                         continue;
 728                 }
 729                 l->backlog[imp].len += skb_queue_len(list);
 730                 skb_queue_splice_tail_init(list, backlogq);
 731         }
 732         l->snd_nxt = seqno;
 733         return 0;
 734 }
 735
 736 /*
 737  * tipc_link_sync_rcv - synchronize broadcast link endpoints.
 738  * Receive the sequence number where we should start receiving and
 739  * acking broadcast packets from a newly added peer node, and open
 740  * up for reception of such packets.
 741  *
 742  * Called with node locked
 743  */
 744 static void tipc_link_sync_rcv(struct tipc_node *n, struct sk_buff *buf)
 745 {
 746         struct tipc_msg *msg = buf_msg(buf);
 747
 748         n->bclink.last_sent = n->bclink.last_in = msg_last_bcast(msg);
 749         n->bclink.recv_permitted = true;
 750         kfree_skb(buf);
 751 }
 752
 753 /*
 754  * tipc_link_push_packets - push unsent packets to bearer
 755  *
 756  * Push out the unsent messages of a link where congestion
 757  * has abated. Node is locked.
 758  *
 759  * Called with node locked
 760  */
 761 void tipc_link_push_packets(struct tipc_link *link)
 762 {
 763         struct sk_buff *skb;
 764         struct tipc_msg *msg;
 765         u16 seqno = link->snd_nxt;
 766         u16 ack = mod(link->rcv_nxt - 1);
 767
 768         while (skb_queue_len(&link->transmq) < link->window) {
 769                 skb = __skb_dequeue(&link->backlogq);
 770                 if (!skb)
 771                         break;
 772                 msg = buf_msg(skb);
 773                 link->backlog[msg_importance(msg)].len--;
 774                 msg_set_ack(msg, ack);
 775                 msg_set_seqno(msg, seqno);
 776                 seqno = mod(seqno + 1);
 777                 msg_set_bcast_ack(msg, link->owner->bclink.last_in);
 778                 link->rcv_unacked = 0;
 779                 __skb_queue_tail(&link->transmq, skb);
 780                 tipc_bearer_send(link->owner->net, link->bearer_id,
 781                                  skb, &link->media_addr);
 782         }
 783         link->snd_nxt = seqno;
 784 }
 785
 786 void tipc_link_advance_backlog(struct tipc_link *l, struct sk_buff_head *xmitq)
 787 {
 788         struct sk_buff *skb, *_skb;
 789         struct tipc_msg *hdr;
 790         u16 seqno = l->snd_nxt;
 791         u16 ack = l->rcv_nxt - 1;
 792
 793         while (skb_queue_len(&l->transmq) < l->window) {
 794                 skb = skb_peek(&l->backlogq);
 795                 if (!skb)
 796                         break;
 797                 _skb = skb_clone(skb, GFP_ATOMIC);
 798                 if (!_skb)
 799                         break;
 800                 __skb_dequeue(&l->backlogq);
 801                 hdr = buf_msg(skb);
 802                 l->backlog[msg_importance(hdr)].len--;
 803                 __skb_queue_tail(&l->transmq, skb);
 804                 __skb_queue_tail(xmitq, _skb);
 805                 msg_set_ack(hdr, ack);
 806                 msg_set_seqno(hdr, seqno);
 807                 msg_set_bcast_ack(hdr, l->owner->bclink.last_in);
 808                 l->rcv_unacked = 0;
 809                 seqno++;
 810         }
 811         l->snd_nxt = seqno;
 812 }
 813
 814 static void link_retransmit_failure(struct tipc_link *l_ptr,
 815                                     struct sk_buff *buf)
 816 {
 817         struct tipc_msg *msg = buf_msg(buf);
 818         struct net *net = l_ptr->owner->net;
 819
 820         pr_warn("Retransmission failure on link <%s>\n", l_ptr->name);
 821
 822         if (l_ptr->addr) {
 823                 /* Handle failure on standard link */
 824                 link_print(l_ptr, "Resetting link ");
 825                 pr_info("Failed msg: usr %u, typ %u, len %u, err %u\n",
 826                         msg_user(msg), msg_type(msg), msg_size(msg),
 827                         msg_errcode(msg));
 828                 pr_info("sqno %u, prev: %x, src: %x\n",
 829                         msg_seqno(msg), msg_prevnode(msg), msg_orignode(msg));
 830         } else {
 831                 /* Handle failure on broadcast link */
 832                 struct tipc_node *n_ptr;
 833                 char addr_string[16];
 834
 835                 pr_info("Msg seq number: %u,  ", msg_seqno(msg));
 836                 pr_cont("Outstanding acks: %lu\n",
 837                         (unsigned long) TIPC_SKB_CB(buf)->handle);
 838
 839                 n_ptr = tipc_bclink_retransmit_to(net);
 840
 841                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 842                 pr_info("Broadcast link info for %s\n", addr_string);
 843                 pr_info("Reception permitted: %d,  Acked: %u\n",
 844                         n_ptr->bclink.recv_permitted,
 845                         n_ptr->bclink.acked);
 846                 pr_info("Last in: %u,  Oos state: %u,  Last sent: %u\n",
 847                         n_ptr->bclink.last_in,
 848                         n_ptr->bclink.oos_state,
 849                         n_ptr->bclink.last_sent);
 850
 851                 n_ptr->action_flags |= TIPC_BCAST_RESET;
 852                 l_ptr->stale_count = 0;
 853         }
 854 }
 855
 856 void tipc_link_retransmit(struct tipc_link *l_ptr, struct sk_buff *skb,
 857                           u32 retransmits)
 858 {
 859         struct tipc_msg *msg;
 860
 861         if (!skb)
 862                 return;
 863
 864         msg = buf_msg(skb);
 865
 866         /* Detect repeated retransmit failures */
 867         if (l_ptr->last_retransm == msg_seqno(msg)) {
 868                 if (++l_ptr->stale_count > 100) {
 869                         link_retransmit_failure(l_ptr, skb);
 870                         return;
 871                 }
 872         } else {
 873                 l_ptr->last_retransm = msg_seqno(msg);
 874                 l_ptr->stale_count = 1;
 875         }
 876
 877         skb_queue_walk_from(&l_ptr->transmq, skb) {
 878                 if (!retransmits)
 879                         break;
 880                 msg = buf_msg(skb);
 881                 msg_set_ack(msg, mod(l_ptr->rcv_nxt - 1));
 882                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
 883                 tipc_bearer_send(l_ptr->owner->net, l_ptr->bearer_id, skb,
 884                                  &l_ptr->media_addr);
 885                 retransmits--;
 886                 l_ptr->stats.retransmitted++;
 887         }
 888 }
 889
 890 static int tipc_link_retransm(struct tipc_link *l, int retransm,
 891                               struct sk_buff_head *xmitq)
 892 {
 893         struct sk_buff *_skb, *skb = skb_peek(&l->transmq);
 894         struct tipc_msg *hdr;
 895
 896         if (!skb)
 897                 return 0;
 898
 899         /* Detect repeated retransmit failures on same packet */
 900         if (likely(l->last_retransm != buf_seqno(skb))) {
 901                 l->last_retransm = buf_seqno(skb);
 902                 l->stale_count = 1;
 903         } else if (++l->stale_count > 100) {
 904                 link_retransmit_failure(l, skb);
 905                 l->exec_mode = TIPC_LINK_BLOCKED;
 906                 return TIPC_LINK_DOWN_EVT;
 907         }
 908         skb_queue_walk(&l->transmq, skb) {
 909                 if (!retransm)
 910                         return 0;
 911                 hdr = buf_msg(skb);
 912                 _skb = __pskb_copy(skb, MIN_H_SIZE, GFP_ATOMIC);
 913                 if (!_skb)
 914                         return 0;
 915                 hdr = buf_msg(_skb);
 916                 msg_set_ack(hdr, l->rcv_nxt - 1);
 917                 msg_set_bcast_ack(hdr, l->owner->bclink.last_in);
 918                 _skb->priority = TC_PRIO_CONTROL;
 919                 __skb_queue_tail(xmitq, _skb);
 920                 retransm--;
 921                 l->stats.retransmitted++;
 922         }
 923         return 0;
 924 }
 925
 926 /* tipc_data_input - deliver data and name distr msgs to upper layer
 927  *
 928  * Consumes buffer if message is of right type
 929  * Node lock must be held
 930  */
 931 static bool tipc_data_input(struct tipc_link *link, struct sk_buff *skb)
 932 {
 933         struct tipc_node *node = link->owner;
 934         struct tipc_msg *msg = buf_msg(skb);
 935         u32 dport = msg_destport(msg);
 936
 937         switch (msg_user(msg)) {
 938         case TIPC_LOW_IMPORTANCE:
 939         case TIPC_MEDIUM_IMPORTANCE:
 940         case TIPC_HIGH_IMPORTANCE:
 941         case TIPC_CRITICAL_IMPORTANCE:
 942         case CONN_MANAGER:
 943                 if (tipc_skb_queue_tail(link->inputq, skb, dport)) {
 944                         node->inputq = link->inputq;
 945                         node->action_flags |= TIPC_MSG_EVT;
 946                 }
 947                 return true;
 948         case NAME_DISTRIBUTOR:
 949                 node->bclink.recv_permitted = true;
 950                 node->namedq = link->namedq;
 951                 skb_queue_tail(link->namedq, skb);
 952                 if (skb_queue_len(link->namedq) == 1)
 953                         node->action_flags |= TIPC_NAMED_MSG_EVT;
 954                 return true;
 955         case MSG_BUNDLER:
 956         case TUNNEL_PROTOCOL:
 957         case MSG_FRAGMENTER:
 958         case BCAST_PROTOCOL:
 959                 return false;
 960         default:
 961                 pr_warn("Dropping received illegal msg type\n");
 962                 kfree_skb(skb);
 963                 return false;
 964         };
 965 }
 966
 967 /* tipc_link_input - process packet that has passed link protocol check
 968  *
 969  * Consumes buffer
 970  */
 971 static int tipc_link_input(struct tipc_link *l, struct sk_buff *skb)
 972 {
 973         struct tipc_node *node = l->owner;
 974         struct tipc_msg *hdr = buf_msg(skb);
 975         struct sk_buff **reasm_skb = &l->reasm_buf;
 976         struct sk_buff *iskb;
 977         int usr = msg_user(hdr);
 978         int rc = 0;
 979         int pos = 0;
 980         int ipos = 0;
 981
 982         if (unlikely(usr == TUNNEL_PROTOCOL)) {
 983                 if (msg_type(hdr) == SYNCH_MSG) {
 984                         __skb_queue_purge(&l->deferdq);
 985                         goto drop;
 986                 }
 987                 if (!tipc_msg_extract(skb, &iskb, &ipos))
 988                         return rc;
 989                 kfree_skb(skb);
 990                 skb = iskb;
 991                 hdr = buf_msg(skb);
 992                 if (less(msg_seqno(hdr), l->drop_point))
 993                         goto drop;
 994                 if (tipc_data_input(l, skb))
 995                         return rc;
 996                 usr = msg_user(hdr);
 997                 reasm_skb = &l->failover_reasm_skb;
 998         }
 999
1000         if (usr == MSG_BUNDLER) {
1001                 l->stats.recv_bundles++;
1002                 l->stats.recv_bundled += msg_msgcnt(hdr);
1003                 while (tipc_msg_extract(skb, &iskb, &pos))
1004                         tipc_data_input(l, iskb);
1005                 return rc;
1006         } else if (usr == MSG_FRAGMENTER) {
1007                 l->stats.recv_fragments++;
1008                 if (tipc_buf_append(reasm_skb, &skb)) {
1009                         l->stats.recv_fragmented++;
1010                         tipc_data_input(l, skb);
1011                 } else if (!*reasm_skb) {
1012                         l->exec_mode = TIPC_LINK_BLOCKED;
1013                         l->state = TIPC_LINK_RESETTING;
1014                         rc = TIPC_LINK_DOWN_EVT;
1015                 }
1016                 return rc;
1017         } else if (usr == BCAST_PROTOCOL) {
1018                 tipc_link_sync_rcv(node, skb);
1019                 return rc;
1020         }
1021 drop:
1022         kfree_skb(skb);
1023         return rc;
1024 }
1025
1026 static bool tipc_link_release_pkts(struct tipc_link *l, u16 acked)
1027 {
1028         bool released = false;
1029         struct sk_buff *skb, *tmp;
1030
1031         skb_queue_walk_safe(&l->transmq, skb, tmp) {
1032                 if (more(buf_seqno(skb), acked))
1033                         break;
1034                 __skb_unlink(skb, &l->transmq);
1035                 kfree_skb(skb);
1036                 released = true;
1037         }
1038         return released;
1039 }
1040
1041 /* tipc_link_rcv - process TIPC packets/messages arriving from off-node
1042  * @link: the link that should handle the message
1043  * @skb: TIPC packet
1044  * @xmitq: queue to place packets to be sent after this call
1045  */
1046 int tipc_link_rcv(struct tipc_link *l, struct sk_buff *skb,
1047                   struct sk_buff_head *xmitq)
1048 {
1049         struct sk_buff_head *arrvq = &l->deferdq;
1050         struct tipc_msg *hdr;
1051         u16 seqno, rcv_nxt;
1052         int rc = 0;
1053
1054         if (unlikely(!__tipc_skb_queue_sorted(arrvq, skb))) {
1055                 if (!(skb_queue_len(arrvq) % TIPC_NACK_INTV))
1056                         tipc_link_build_proto_msg(l, STATE_MSG, 0,
1057                                                   0, 0, 0, xmitq);
1058                 return rc;
1059         }
1060
1061         while ((skb = skb_peek(arrvq))) {
1062                 hdr = buf_msg(skb);
1063
1064                 /* Verify and update link state */
1065                 if (unlikely(msg_user(hdr) == LINK_PROTOCOL)) {
1066                         __skb_dequeue(arrvq);
1067                         rc = tipc_link_proto_rcv(l, skb, xmitq);
1068                         continue;
1069                 }
1070
1071                 if (unlikely(!link_working(l))) {
1072                         rc = tipc_link_fsm_evt(l, TRAFFIC_EVT, xmitq);
1073                         if (!link_working(l)) {
1074                                 kfree_skb(__skb_dequeue(arrvq));
1075                                 return rc;
1076                         }
1077                 }
1078
1079                 l->silent_intv_cnt = 0;
1080
1081                 /* Forward queues and wake up waiting users */
1082                 if (likely(tipc_link_release_pkts(l, msg_ack(hdr)))) {
1083                         tipc_link_advance_backlog(l, xmitq);
1084                         if (unlikely(!skb_queue_empty(&l->wakeupq)))
1085                                 link_prepare_wakeup(l);
1086                 }
1087
1088                 /* Defer reception if there is a gap in the sequence */
1089                 seqno = msg_seqno(hdr);
1090                 rcv_nxt = l->rcv_nxt;
1091                 if (unlikely(less(rcv_nxt, seqno))) {
1092                         l->stats.deferred_recv++;
1093                         return rc;
1094                 }
1095
1096                 __skb_dequeue(arrvq);
1097
1098                 /* Drop if packet already received */
1099                 if (unlikely(more(rcv_nxt, seqno))) {
1100                         l->stats.duplicates++;
1101                         kfree_skb(skb);
1102                         return rc;
1103                 }
1104
1105                 /* Packet can be delivered */
1106                 l->rcv_nxt++;
1107                 l->stats.recv_info++;
1108                 if (unlikely(!tipc_data_input(l, skb)))
1109                         rc = tipc_link_input(l, skb);
1110
1111                 /* Ack at regular intervals */
1112                 if (unlikely(++l->rcv_unacked >= TIPC_MIN_LINK_WIN)) {
1113                         l->rcv_unacked = 0;
1114                         l->stats.sent_acks++;
1115                         tipc_link_build_proto_msg(l, STATE_MSG,
1116                                                   0, 0, 0, 0, xmitq);
1117                 }
1118         }
1119         return rc;
1120 }
1121
1122 /**
1123  * tipc_link_defer_pkt - Add out-of-sequence message to deferred reception queue
1124  *
1125  * Returns increase in queue length (i.e. 0 or 1)
1126  */
1127 u32 tipc_link_defer_pkt(struct sk_buff_head *list, struct sk_buff *skb)
1128 {
1129         struct sk_buff *skb1;
1130         u16 seq_no = buf_seqno(skb);
1131
1132         /* Empty queue ? */
1133         if (skb_queue_empty(list)) {
1134                 __skb_queue_tail(list, skb);
1135                 return 1;
1136         }
1137
1138         /* Last ? */
1139         if (less(buf_seqno(skb_peek_tail(list)), seq_no)) {
1140                 __skb_queue_tail(list, skb);
1141                 return 1;
1142         }
1143
1144         /* Locate insertion point in queue, then insert; discard if duplicate */
1145         skb_queue_walk(list, skb1) {
1146                 u16 curr_seqno = buf_seqno(skb1);
1147
1148                 if (seq_no == curr_seqno) {
1149                         kfree_skb(skb);
1150                         return 0;
1151                 }
1152
1153                 if (less(seq_no, curr_seqno))
1154                         break;
1155         }
1156
1157         __skb_queue_before(list, skb1, skb);
1158         return 1;
1159 }
1160
1161 /*
1162  * Send protocol message to the other endpoint.
1163  */
1164 void tipc_link_proto_xmit(struct tipc_link *l, u32 msg_typ, int probe_msg,
1165                           u32 gap, u32 tolerance, u32 priority)
1166 {
1167         struct sk_buff *skb = NULL;
1168         struct sk_buff_head xmitq;
1169
1170         __skb_queue_head_init(&xmitq);
1171         tipc_link_build_proto_msg(l, msg_typ, probe_msg, gap,
1172                                   tolerance, priority, &xmitq);
1173         skb = __skb_dequeue(&xmitq);
1174         if (!skb)
1175                 return;
1176         tipc_bearer_send(l->owner->net, l->bearer_id, skb, &l->media_addr);
1177         l->rcv_unacked = 0;
1178         kfree_skb(skb);
1179 }
1180
1181 /* tipc_link_build_proto_msg: prepare link protocol message for transmission
1182  */
1183 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
1184                                       u16 rcvgap, int tolerance, int priority,
1185                                       struct sk_buff_head *xmitq)
1186 {
1187         struct sk_buff *skb = NULL;
1188         struct tipc_msg *hdr = l->pmsg;
1189         u16 snd_nxt = l->snd_nxt;
1190         u16 rcv_nxt = l->rcv_nxt;
1191         u16 rcv_last = rcv_nxt - 1;
1192         int node_up = l->owner->bclink.recv_permitted;
1193
1194         /* Don't send protocol message during reset or link failover */
1195         if (l->exec_mode == TIPC_LINK_BLOCKED)
1196                 return;
1197
1198         msg_set_type(hdr, mtyp);
1199         msg_set_net_plane(hdr, l->net_plane);
1200         msg_set_bcast_ack(hdr, l->owner->bclink.last_in);
1201         msg_set_last_bcast(hdr, tipc_bclink_get_last_sent(l->owner->net));
1202         msg_set_link_tolerance(hdr, tolerance);
1203         msg_set_linkprio(hdr, priority);
1204         msg_set_redundant_link(hdr, node_up);
1205         msg_set_seq_gap(hdr, 0);
1206
1207         /* Compatibility: created msg must not be in sequence with pkt flow */
1208         msg_set_seqno(hdr, snd_nxt + U16_MAX / 2);
1209
1210         if (mtyp == STATE_MSG) {
1211                 if (!tipc_link_is_up(l))
1212                         return;
1213                 msg_set_next_sent(hdr, snd_nxt);
1214
1215                 /* Override rcvgap if there are packets in deferred queue */
1216                 if (!skb_queue_empty(&l->deferdq))
1217                         rcvgap = buf_seqno(skb_peek(&l->deferdq)) - rcv_nxt;
1218                 if (rcvgap) {
1219                         msg_set_seq_gap(hdr, rcvgap);
1220                         l->stats.sent_nacks++;
1221                 }
1222                 msg_set_ack(hdr, rcv_last);
1223                 msg_set_probe(hdr, probe);
1224                 if (probe)
1225                         l->stats.sent_probes++;
1226                 l->stats.sent_states++;
1227         } else {
1228                 /* RESET_MSG or ACTIVATE_MSG */
1229                 msg_set_max_pkt(hdr, l->advertised_mtu);
1230                 msg_set_ack(hdr, l->rcv_nxt - 1);
1231                 msg_set_next_sent(hdr, 1);
1232         }
1233         skb = tipc_buf_acquire(msg_size(hdr));
1234         if (!skb)
1235                 return;
1236         skb_copy_to_linear_data(skb, hdr, msg_size(hdr));
1237         skb->priority = TC_PRIO_CONTROL;
1238         __skb_queue_tail(xmitq, skb);
1239 }
1240
1241 /* tipc_link_tnl_prepare(): prepare and return a list of tunnel packets
1242  * with contents of the link's tranmsit and backlog queues.
1243  */
1244 void tipc_link_tnl_prepare(struct tipc_link *l, struct tipc_link *tnl,
1245                            int mtyp, struct sk_buff_head *xmitq)
1246 {
1247         struct sk_buff *skb, *tnlskb;
1248         struct tipc_msg *hdr, tnlhdr;
1249         struct sk_buff_head *queue = &l->transmq;
1250         struct sk_buff_head tmpxq, tnlq;
1251         u16 pktlen, pktcnt, seqno = l->snd_nxt;
1252
1253         if (!tnl)
1254                 return;
1255
1256         skb_queue_head_init(&tnlq);
1257         skb_queue_head_init(&tmpxq);
1258
1259         /* At least one packet required for safe algorithm => add dummy */
1260         skb = tipc_msg_create(TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
1261                               BASIC_H_SIZE, 0, l->addr, link_own_addr(l),
1262                               0, 0, TIPC_ERR_NO_PORT);
1263         if (!skb) {
1264                 pr_warn("%sunable to create tunnel packet\n", link_co_err);
1265                 return;
1266         }
1267         skb_queue_tail(&tnlq, skb);
1268         tipc_link_xmit(l, &tnlq, &tmpxq);
1269         __skb_queue_purge(&tmpxq);
1270
1271         /* Initialize reusable tunnel packet header */
1272         tipc_msg_init(link_own_addr(l), &tnlhdr, TUNNEL_PROTOCOL,
1273                       mtyp, INT_H_SIZE, l->addr);
1274         pktcnt = skb_queue_len(&l->transmq) + skb_queue_len(&l->backlogq);
1275         msg_set_msgcnt(&tnlhdr, pktcnt);
1276         msg_set_bearer_id(&tnlhdr, l->peer_bearer_id);
1277 tnl:
1278         /* Wrap each packet into a tunnel packet */
1279         skb_queue_walk(queue, skb) {
1280                 hdr = buf_msg(skb);
1281                 if (queue == &l->backlogq)
1282                         msg_set_seqno(hdr, seqno++);
1283                 pktlen = msg_size(hdr);
1284                 msg_set_size(&tnlhdr, pktlen + INT_H_SIZE);
1285                 tnlskb = tipc_buf_acquire(pktlen + INT_H_SIZE);
1286                 if (!tnlskb) {
1287                         pr_warn("%sunable to send packet\n", link_co_err);
1288                         return;
1289                 }
1290                 skb_copy_to_linear_data(tnlskb, &tnlhdr, INT_H_SIZE);
1291                 skb_copy_to_linear_data_offset(tnlskb, INT_H_SIZE, hdr, pktlen);
1292                 __skb_queue_tail(&tnlq, tnlskb);
1293         }
1294         if (queue != &l->backlogq) {
1295                 queue = &l->backlogq;
1296                 goto tnl;
1297         }
1298
1299         tipc_link_xmit(tnl, &tnlq, xmitq);
1300
1301         if (mtyp == FAILOVER_MSG) {
1302                 tnl->drop_point = l->rcv_nxt;
1303                 tnl->failover_reasm_skb = l->reasm_buf;
1304                 l->reasm_buf = NULL;
1305                 l->exec_mode = TIPC_LINK_BLOCKED;
1306         }
1307 }
1308
1309 /* tipc_link_proto_rcv(): receive link level protocol message :
1310  * Note that network plane id propagates through the network, and may
1311  * change at any time. The node with lowest numerical id determines
1312  * network plane
1313  */
1314 static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
1315                                struct sk_buff_head *xmitq)
1316 {
1317         struct tipc_msg *hdr = buf_msg(skb);
1318         u16 rcvgap = 0;
1319         u16 nacked_gap = msg_seq_gap(hdr);
1320         u16 peers_snd_nxt =  msg_next_sent(hdr);
1321         u16 peers_tol = msg_link_tolerance(hdr);
1322         u16 peers_prio = msg_linkprio(hdr);
1323         char *if_name;
1324         int rc = 0;
1325
1326         if (l->exec_mode == TIPC_LINK_BLOCKED)
1327                 goto exit;
1328
1329         if (link_own_addr(l) > msg_prevnode(hdr))
1330                 l->net_plane = msg_net_plane(hdr);
1331
1332         switch (msg_type(hdr)) {
1333         case RESET_MSG:
1334
1335                 /* Ignore duplicate RESET with old session number */
1336                 if ((less_eq(msg_session(hdr), l->peer_session)) &&
1337                     (l->peer_session != WILDCARD_SESSION))
1338                         break;
1339                 /* fall thru' */
1340         case ACTIVATE_MSG:
1341
1342                 /* Complete own link name with peer's interface name */
1343                 if_name =  strrchr(l->name, ':') + 1;
1344                 if (sizeof(l->name) - (if_name - l->name) <= TIPC_MAX_IF_NAME)
1345                         break;
1346                 if (msg_data_sz(hdr) < TIPC_MAX_IF_NAME)
1347                         break;
1348                 strncpy(if_name, msg_data(hdr), TIPC_MAX_IF_NAME);
1349
1350                 /* Update own tolerance if peer indicates a non-zero value */
1351                 if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL))
1352                         l->tolerance = peers_tol;
1353
1354                 /* Update own priority if peer's priority is higher */
1355                 if (in_range(peers_prio, l->priority + 1, TIPC_MAX_LINK_PRI))
1356                         l->priority = peers_prio;
1357
1358                 l->peer_session = msg_session(hdr);
1359                 l->peer_bearer_id = msg_bearer_id(hdr);
1360                 rc = tipc_link_fsm_evt(l, msg_type(hdr), xmitq);
1361                 if (l->mtu > msg_max_pkt(hdr))
1362                         l->mtu = msg_max_pkt(hdr);
1363                 break;
1364         case STATE_MSG:
1365                 /* Update own tolerance if peer indicates a non-zero value */
1366                 if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL))
1367                         l->tolerance = peers_tol;
1368
1369                 l->silent_intv_cnt = 0;
1370                 l->stats.recv_states++;
1371                 if (msg_probe(hdr))
1372                         l->stats.recv_probes++;
1373                 rc = tipc_link_fsm_evt(l, TRAFFIC_EVT, xmitq);
1374                 if (!tipc_link_is_up(l))
1375                         break;
1376
1377                 /* Has peer sent packets we haven't received yet ? */
1378                 if (more(peers_snd_nxt, l->rcv_nxt))
1379                         rcvgap = peers_snd_nxt - l->rcv_nxt;
1380                 if (rcvgap || (msg_probe(hdr)))
1381                         tipc_link_build_proto_msg(l, STATE_MSG, 0, rcvgap,
1382                                                   0, 0, xmitq);
1383                 tipc_link_release_pkts(l, msg_ack(hdr));
1384
1385                 /* If NACK, retransmit will now start at right position */
1386                 if (nacked_gap) {
1387                         rc = tipc_link_retransm(l, nacked_gap, xmitq);
1388                         l->stats.recv_nacks++;
1389                 }
1390                 tipc_link_advance_backlog(l, xmitq);
1391                 if (unlikely(!skb_queue_empty(&l->wakeupq)))
1392                         link_prepare_wakeup(l);
1393         }
1394 exit:
1395         kfree_skb(skb);
1396         return rc;
1397 }
1398
1399 void tipc_link_set_queue_limits(struct tipc_link *l, u32 win)
1400 {
1401         int max_bulk = TIPC_MAX_PUBLICATIONS / (l->mtu / ITEM_SIZE);
1402
1403         l->window = win;
1404         l->backlog[TIPC_LOW_IMPORTANCE].limit      = win / 2;
1405         l->backlog[TIPC_MEDIUM_IMPORTANCE].limit   = win;
1406         l->backlog[TIPC_HIGH_IMPORTANCE].limit     = win / 2 * 3;
1407         l->backlog[TIPC_CRITICAL_IMPORTANCE].limit = win * 2;
1408         l->backlog[TIPC_SYSTEM_IMPORTANCE].limit   = max_bulk;
1409 }
1410
1411 /* tipc_link_find_owner - locate owner node of link by link's name
1412  * @net: the applicable net namespace
1413  * @name: pointer to link name string
1414  * @bearer_id: pointer to index in 'node->links' array where the link was found.
1415  *
1416  * Returns pointer to node owning the link, or 0 if no matching link is found.
1417  */
1418 static struct tipc_node *tipc_link_find_owner(struct net *net,
1419                                               const char *link_name,
1420                                               unsigned int *bearer_id)
1421 {
1422         struct tipc_net *tn = net_generic(net, tipc_net_id);
1423         struct tipc_link *l_ptr;
1424         struct tipc_node *n_ptr;
1425         struct tipc_node *found_node = NULL;
1426         int i;
1427
1428         *bearer_id = 0;
1429         rcu_read_lock();
1430         list_for_each_entry_rcu(n_ptr, &tn->node_list, list) {
1431                 tipc_node_lock(n_ptr);
1432                 for (i = 0; i < MAX_BEARERS; i++) {
1433                         l_ptr = n_ptr->links[i].link;
1434                         if (l_ptr && !strcmp(l_ptr->name, link_name)) {
1435                                 *bearer_id = i;
1436                                 found_node = n_ptr;
1437                                 break;
1438                         }
1439                 }
1440                 tipc_node_unlock(n_ptr);
1441                 if (found_node)
1442                         break;
1443         }
1444         rcu_read_unlock();
1445
1446         return found_node;
1447 }
1448
1449 /**
1450  * link_reset_statistics - reset link statistics
1451  * @l_ptr: pointer to link
1452  */
1453 static void link_reset_statistics(struct tipc_link *l_ptr)
1454 {
1455         memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
1456         l_ptr->stats.sent_info = l_ptr->snd_nxt;
1457         l_ptr->stats.recv_info = l_ptr->rcv_nxt;
1458 }
1459
1460 static void link_print(struct tipc_link *l, const char *str)
1461 {
1462         struct sk_buff *hskb = skb_peek(&l->transmq);
1463         u16 head = hskb ? msg_seqno(buf_msg(hskb)) : l->snd_nxt;
1464         u16 tail = l->snd_nxt - 1;
1465
1466         pr_info("%s Link <%s>:", str, l->name);
1467
1468         if (link_probing(l))
1469                 pr_cont(":P\n");
1470         else if (link_establishing(l))
1471                 pr_cont(":E\n");
1472         else if (link_resetting(l))
1473                 pr_cont(":R\n");
1474         else if (link_working(l))
1475                 pr_cont(":W\n");
1476         else
1477                 pr_cont("\n");
1478
1479         pr_info("XMTQ: %u [%u-%u], BKLGQ: %u, SNDNX: %u, RCVNX: %u\n",
1480                 skb_queue_len(&l->transmq), head, tail,
1481                 skb_queue_len(&l->backlogq), l->snd_nxt, l->rcv_nxt);
1482 }
1483
1484 /* Parse and validate nested (link) properties valid for media, bearer and link
1485  */
1486 int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[])
1487 {
1488         int err;
1489
1490         err = nla_parse_nested(props, TIPC_NLA_PROP_MAX, prop,
1491                                tipc_nl_prop_policy);
1492         if (err)
1493                 return err;
1494
1495         if (props[TIPC_NLA_PROP_PRIO]) {
1496                 u32 prio;
1497
1498                 prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1499                 if (prio > TIPC_MAX_LINK_PRI)
1500                         return -EINVAL;
1501         }
1502
1503         if (props[TIPC_NLA_PROP_TOL]) {
1504                 u32 tol;
1505
1506                 tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1507                 if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
1508                         return -EINVAL;
1509         }
1510
1511         if (props[TIPC_NLA_PROP_WIN]) {
1512                 u32 win;
1513
1514                 win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
1515                 if ((win < TIPC_MIN_LINK_WIN) || (win > TIPC_MAX_LINK_WIN))
1516                         return -EINVAL;
1517         }
1518
1519         return 0;
1520 }
1521
1522 int tipc_nl_link_set(struct sk_buff *skb, struct genl_info *info)
1523 {
1524         int err;
1525         int res = 0;
1526         int bearer_id;
1527         char *name;
1528         struct tipc_link *link;
1529         struct tipc_node *node;
1530         struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
1531         struct net *net = sock_net(skb->sk);
1532
1533         if (!info->attrs[TIPC_NLA_LINK])
1534                 return -EINVAL;
1535
1536         err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
1537                                info->attrs[TIPC_NLA_LINK],
1538                                tipc_nl_link_policy);
1539         if (err)
1540                 return err;
1541
1542         if (!attrs[TIPC_NLA_LINK_NAME])
1543                 return -EINVAL;
1544
1545         name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
1546
1547         if (strcmp(name, tipc_bclink_name) == 0)
1548                 return tipc_nl_bc_link_set(net, attrs);
1549
1550         node = tipc_link_find_owner(net, name, &bearer_id);
1551         if (!node)
1552                 return -EINVAL;
1553
1554         tipc_node_lock(node);
1555
1556         link = node->links[bearer_id].link;
1557         if (!link) {
1558                 res = -EINVAL;
1559                 goto out;
1560         }
1561
1562         if (attrs[TIPC_NLA_LINK_PROP]) {
1563                 struct nlattr *props[TIPC_NLA_PROP_MAX + 1];
1564
1565                 err = tipc_nl_parse_link_prop(attrs[TIPC_NLA_LINK_PROP],
1566                                               props);
1567                 if (err) {
1568                         res = err;
1569                         goto out;
1570                 }
1571
1572                 if (props[TIPC_NLA_PROP_TOL]) {
1573                         u32 tol;
1574
1575                         tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1576                         link->tolerance = tol;
1577                         tipc_link_proto_xmit(link, STATE_MSG, 0, 0, tol, 0);
1578                 }
1579                 if (props[TIPC_NLA_PROP_PRIO]) {
1580                         u32 prio;
1581
1582                         prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1583                         link->priority = prio;
1584                         tipc_link_proto_xmit(link, STATE_MSG, 0, 0, 0, prio);
1585                 }
1586                 if (props[TIPC_NLA_PROP_WIN]) {
1587                         u32 win;
1588
1589                         win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
1590                         tipc_link_set_queue_limits(link, win);
1591                 }
1592         }
1593
1594 out:
1595         tipc_node_unlock(node);
1596
1597         return res;
1598 }
1599
1600 static int __tipc_nl_add_stats(struct sk_buff *skb, struct tipc_stats *s)
1601 {
1602         int i;
1603         struct nlattr *stats;
1604
1605         struct nla_map {
1606                 u32 key;
1607                 u32 val;
1608         };
1609
1610         struct nla_map map[] = {
1611                 {TIPC_NLA_STATS_RX_INFO, s->recv_info},
1612                 {TIPC_NLA_STATS_RX_FRAGMENTS, s->recv_fragments},
1613                 {TIPC_NLA_STATS_RX_FRAGMENTED, s->recv_fragmented},
1614                 {TIPC_NLA_STATS_RX_BUNDLES, s->recv_bundles},
1615                 {TIPC_NLA_STATS_RX_BUNDLED, s->recv_bundled},
1616                 {TIPC_NLA_STATS_TX_INFO, s->sent_info},
1617                 {TIPC_NLA_STATS_TX_FRAGMENTS, s->sent_fragments},
1618                 {TIPC_NLA_STATS_TX_FRAGMENTED, s->sent_fragmented},
1619                 {TIPC_NLA_STATS_TX_BUNDLES, s->sent_bundles},
1620                 {TIPC_NLA_STATS_TX_BUNDLED, s->sent_bundled},
1621                 {TIPC_NLA_STATS_MSG_PROF_TOT, (s->msg_length_counts) ?
1622                         s->msg_length_counts : 1},
1623                 {TIPC_NLA_STATS_MSG_LEN_CNT, s->msg_length_counts},
1624                 {TIPC_NLA_STATS_MSG_LEN_TOT, s->msg_lengths_total},
1625                 {TIPC_NLA_STATS_MSG_LEN_P0, s->msg_length_profile[0]},
1626                 {TIPC_NLA_STATS_MSG_LEN_P1, s->msg_length_profile[1]},
1627                 {TIPC_NLA_STATS_MSG_LEN_P2, s->msg_length_profile[2]},
1628                 {TIPC_NLA_STATS_MSG_LEN_P3, s->msg_length_profile[3]},
1629                 {TIPC_NLA_STATS_MSG_LEN_P4, s->msg_length_profile[4]},
1630                 {TIPC_NLA_STATS_MSG_LEN_P5, s->msg_length_profile[5]},
1631                 {TIPC_NLA_STATS_MSG_LEN_P6, s->msg_length_profile[6]},
1632                 {TIPC_NLA_STATS_RX_STATES, s->recv_states},
1633                 {TIPC_NLA_STATS_RX_PROBES, s->recv_probes},
1634                 {TIPC_NLA_STATS_RX_NACKS, s->recv_nacks},
1635                 {TIPC_NLA_STATS_RX_DEFERRED, s->deferred_recv},
1636                 {TIPC_NLA_STATS_TX_STATES, s->sent_states},
1637                 {TIPC_NLA_STATS_TX_PROBES, s->sent_probes},
1638                 {TIPC_NLA_STATS_TX_NACKS, s->sent_nacks},
1639                 {TIPC_NLA_STATS_TX_ACKS, s->sent_acks},
1640                 {TIPC_NLA_STATS_RETRANSMITTED, s->retransmitted},
1641                 {TIPC_NLA_STATS_DUPLICATES, s->duplicates},
1642                 {TIPC_NLA_STATS_LINK_CONGS, s->link_congs},
1643                 {TIPC_NLA_STATS_MAX_QUEUE, s->max_queue_sz},
1644                 {TIPC_NLA_STATS_AVG_QUEUE, s->queue_sz_counts ?
1645                         (s->accu_queue_sz / s->queue_sz_counts) : 0}
1646         };
1647
1648         stats = nla_nest_start(skb, TIPC_NLA_LINK_STATS);
1649         if (!stats)
1650                 return -EMSGSIZE;
1651
1652         for (i = 0; i <  ARRAY_SIZE(map); i++)
1653                 if (nla_put_u32(skb, map[i].key, map[i].val))
1654                         goto msg_full;
1655
1656         nla_nest_end(skb, stats);
1657
1658         return 0;
1659 msg_full:
1660         nla_nest_cancel(skb, stats);
1661
1662         return -EMSGSIZE;
1663 }
1664
1665 /* Caller should hold appropriate locks to protect the link */
1666 static int __tipc_nl_add_link(struct net *net, struct tipc_nl_msg *msg,
1667                               struct tipc_link *link, int nlflags)
1668 {
1669         int err;
1670         void *hdr;
1671         struct nlattr *attrs;
1672         struct nlattr *prop;
1673         struct tipc_net *tn = net_generic(net, tipc_net_id);
1674
1675         hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
1676                           nlflags, TIPC_NL_LINK_GET);
1677         if (!hdr)
1678                 return -EMSGSIZE;
1679
1680         attrs = nla_nest_start(msg->skb, TIPC_NLA_LINK);
1681         if (!attrs)
1682                 goto msg_full;
1683
1684         if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, link->name))
1685                 goto attr_msg_full;
1686         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_DEST,
1687                         tipc_cluster_mask(tn->own_addr)))
1688                 goto attr_msg_full;
1689         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_MTU, link->mtu))
1690                 goto attr_msg_full;
1691         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, link->rcv_nxt))
1692                 goto attr_msg_full;
1693         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, link->snd_nxt))
1694                 goto attr_msg_full;
1695
1696         if (tipc_link_is_up(link))
1697                 if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
1698                         goto attr_msg_full;
1699         if (tipc_link_is_active(link))
1700                 if (nla_put_flag(msg->skb, TIPC_NLA_LINK_ACTIVE))
1701                         goto attr_msg_full;
1702
1703         prop = nla_nest_start(msg->skb, TIPC_NLA_LINK_PROP);
1704         if (!prop)
1705                 goto attr_msg_full;
1706         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
1707                 goto prop_msg_full;
1708         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_TOL, link->tolerance))
1709                 goto prop_msg_full;
1710         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN,
1711                         link->window))
1712                 goto prop_msg_full;
1713         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
1714                 goto prop_msg_full;
1715         nla_nest_end(msg->skb, prop);
1716
1717         err = __tipc_nl_add_stats(msg->skb, &link->stats);
1718         if (err)
1719                 goto attr_msg_full;
1720
1721         nla_nest_end(msg->skb, attrs);
1722         genlmsg_end(msg->skb, hdr);
1723
1724         return 0;
1725
1726 prop_msg_full:
1727         nla_nest_cancel(msg->skb, prop);
1728 attr_msg_full:
1729         nla_nest_cancel(msg->skb, attrs);
1730 msg_full:
1731         genlmsg_cancel(msg->skb, hdr);
1732
1733         return -EMSGSIZE;
1734 }
1735
1736 /* Caller should hold node lock  */
1737 static int __tipc_nl_add_node_links(struct net *net, struct tipc_nl_msg *msg,
1738                                     struct tipc_node *node, u32 *prev_link)
1739 {
1740         u32 i;
1741         int err;
1742
1743         for (i = *prev_link; i < MAX_BEARERS; i++) {
1744                 *prev_link = i;
1745
1746                 if (!node->links[i].link)
1747                         continue;
1748
1749                 err = __tipc_nl_add_link(net, msg,
1750                                          node->links[i].link, NLM_F_MULTI);
1751                 if (err)
1752                         return err;
1753         }
1754         *prev_link = 0;
1755
1756         return 0;
1757 }
1758
1759 int tipc_nl_link_dump(struct sk_buff *skb, struct netlink_callback *cb)
1760 {
1761         struct net *net = sock_net(skb->sk);
1762         struct tipc_net *tn = net_generic(net, tipc_net_id);
1763         struct tipc_node *node;
1764         struct tipc_nl_msg msg;
1765         u32 prev_node = cb->args[0];
1766         u32 prev_link = cb->args[1];
1767         int done = cb->args[2];
1768         int err;
1769
1770         if (done)
1771                 return 0;
1772
1773         msg.skb = skb;
1774         msg.portid = NETLINK_CB(cb->skb).portid;
1775         msg.seq = cb->nlh->nlmsg_seq;
1776
1777         rcu_read_lock();
1778         if (prev_node) {
1779                 node = tipc_node_find(net, prev_node);
1780                 if (!node) {
1781                         /* We never set seq or call nl_dump_check_consistent()
1782                          * this means that setting prev_seq here will cause the
1783                          * consistence check to fail in the netlink callback
1784                          * handler. Resulting in the last NLMSG_DONE message
1785                          * having the NLM_F_DUMP_INTR flag set.
1786                          */
1787                         cb->prev_seq = 1;
1788                         goto out;
1789                 }
1790                 tipc_node_put(node);
1791
1792                 list_for_each_entry_continue_rcu(node, &tn->node_list,
1793                                                  list) {
1794                         tipc_node_lock(node);
1795                         err = __tipc_nl_add_node_links(net, &msg, node,
1796                                                        &prev_link);
1797                         tipc_node_unlock(node);
1798                         if (err)
1799                                 goto out;
1800
1801                         prev_node = node->addr;
1802                 }
1803         } else {
1804                 err = tipc_nl_add_bc_link(net, &msg);
1805                 if (err)
1806                         goto out;
1807
1808                 list_for_each_entry_rcu(node, &tn->node_list, list) {
1809                         tipc_node_lock(node);
1810                         err = __tipc_nl_add_node_links(net, &msg, node,
1811                                                        &prev_link);
1812                         tipc_node_unlock(node);
1813                         if (err)
1814                                 goto out;
1815
1816                         prev_node = node->addr;
1817                 }
1818         }
1819         done = 1;
1820 out:
1821         rcu_read_unlock();
1822
1823         cb->args[0] = prev_node;
1824         cb->args[1] = prev_link;
1825         cb->args[2] = done;
1826
1827         return skb->len;
1828 }
1829
1830 int tipc_nl_link_get(struct sk_buff *skb, struct genl_info *info)
1831 {
1832         struct net *net = genl_info_net(info);
1833         struct tipc_nl_msg msg;
1834         char *name;
1835         int err;
1836
1837         msg.portid = info->snd_portid;
1838         msg.seq = info->snd_seq;
1839
1840         if (!info->attrs[TIPC_NLA_LINK_NAME])
1841                 return -EINVAL;
1842         name = nla_data(info->attrs[TIPC_NLA_LINK_NAME]);
1843
1844         msg.skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
1845         if (!msg.skb)
1846                 return -ENOMEM;
1847
1848         if (strcmp(name, tipc_bclink_name) == 0) {
1849                 err = tipc_nl_add_bc_link(net, &msg);
1850                 if (err) {
1851                         nlmsg_free(msg.skb);
1852                         return err;
1853                 }
1854         } else {
1855                 int bearer_id;
1856                 struct tipc_node *node;
1857                 struct tipc_link *link;
1858
1859                 node = tipc_link_find_owner(net, name, &bearer_id);
1860                 if (!node)
1861                         return -EINVAL;
1862
1863                 tipc_node_lock(node);
1864                 link = node->links[bearer_id].link;
1865                 if (!link) {
1866                         tipc_node_unlock(node);
1867                         nlmsg_free(msg.skb);
1868                         return -EINVAL;
1869                 }
1870
1871                 err = __tipc_nl_add_link(net, &msg, link, 0);
1872                 tipc_node_unlock(node);
1873                 if (err) {
1874                         nlmsg_free(msg.skb);
1875                         return err;
1876                 }
1877         }
1878
1879         return genlmsg_reply(msg.skb, info);
1880 }
1881
1882 int tipc_nl_link_reset_stats(struct sk_buff *skb, struct genl_info *info)
1883 {
1884         int err;
1885         char *link_name;
1886         unsigned int bearer_id;
1887         struct tipc_link *link;
1888         struct tipc_node *node;
1889         struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
1890         struct net *net = sock_net(skb->sk);
1891
1892         if (!info->attrs[TIPC_NLA_LINK])
1893                 return -EINVAL;
1894
1895         err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
1896                                info->attrs[TIPC_NLA_LINK],
1897                                tipc_nl_link_policy);
1898         if (err)
1899                 return err;
1900
1901         if (!attrs[TIPC_NLA_LINK_NAME])
1902                 return -EINVAL;
1903
1904         link_name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
1905
1906         if (strcmp(link_name, tipc_bclink_name) == 0) {
1907                 err = tipc_bclink_reset_stats(net);
1908                 if (err)
1909                         return err;
1910                 return 0;
1911         }
1912
1913         node = tipc_link_find_owner(net, link_name, &bearer_id);
1914         if (!node)
1915                 return -EINVAL;
1916
1917         tipc_node_lock(node);
1918
1919         link = node->links[bearer_id].link;
1920         if (!link) {
1921                 tipc_node_unlock(node);
1922                 return -EINVAL;
1923         }
1924
1925         link_reset_statistics(link);
1926
1927         tipc_node_unlock(node);
1928
1929         return 0;
1930 }